Donald Akech, Kenya
KEMRI-Wellcome Trust Research Programme,Kilifi Epidemiology and DemographyAuthor Of 2 Presentations
ANTIMICROBIAL RESISTANCE PATTERNS IN PNEUMOCOCCAL CARRIAGE PRE AND POST PCV10 INTRODUCTION IN NIGERIA (ID 521)
Abstract
Background
Pneumococcal conjugate vaccines (PCVs) reduce antimicrobial resistance (AMR). In Africa, where disease surveillance is limited, nasopharyngeal carriage studies may reveal PCV impact on AMR . We investigated AMR in pneumococcal carriage in Nigeria.
Methods
Nigeria introduced PCV10 between 2014-2016. Random carriage surveys targeting 1000 participants were conducted pre-(2016) and post-PCV10 (2017-2018) in two locations (rural and urban). PCV10 coverage in 2017 and 2018 was 47% and 55%, respectively. Isolates randomly selected from each survey were tested for antimicrobial resistance using broth micro-dilution.
Results
In 571 pneumococcal isolates, prevalence of resistance was -Tetracycline (69%), Cotrimoxazole (68%), Penicillin (43%) and Chloramphenicol (14%). Serotypes 19F, 6A, 11A, 23F, 3, 16F, 19A, 34 and 6B had a high prevalence of resistance. Prevalence of resistance to any antibiotic differed little by pre- vs post-PCV10 era both overall (86% and 85%) and in rural (73% and 71%) and urban (99% and 98%) samples. No difference was seen in prevalence of resistance among vaccine and non-vaccine serotypes by PCV10 era.
Conclusions
Among healthy Nigerians, prevalence of resistance to commonly used antibiotics is high in carried pneumococci. Although the data do not show any impact of PCV10 on resistance prevalence, the lack of effect may be explained by incomplete coverage levels.
LONG-TERM TRENDS IN NASOPHARYNGEAL CARRIAGE OF VACCINE-TYPE PNEUMOCOCCI: FINDINGS FROM A MATURE 10-VALENT PNEUMOCOCCAL CONJUGATE VACCINE (PCV10) PROGRAM IN KENYA (ID 966)
Abstract
Background
PCV10 was introduced into Kenya’s immunization program in 2011, with catchup in children aged 1-4 years. We evaluated the long-term effect of PCV10 on nasopharyngeal carriage of Streptococcus pneumoniae serotypes included in PCV10.
Methods
Population-based annual cross-sectional nasopharyngeal carriage surveys were conducted in randomly selected individuals between 2009 and 2019 (N= ~1000 in 2019; N= ~500 in all others) in Kilifi, Kenya. Pneumococcal identification was performed per WHO standards. Annual vaccine-type carriage prevalence was modelled using log-binomial regression with a curved function for year and adjustment for age-specific sampling probability.
Results
Compared to 2010, carriage of PCV10-type pneumococci declined significantly through 2019 in children aged <5 years to 6.1% (adjusted prevalence ratio 0.18, 95%CI 0.11-0.30) but not in children aged 5-14 years (prevalence= 7.1%; 0.71, 0.38-1.34) nor adults ≥15 years (prevalence= 1.0%; 0.49, 0.17-1.35). PCV10-type carriage was significantly lower in 2017 compared to 2010 for all age groups and did not differ from carriage prevalence in 2019 (figure).
Conclusions
PCV10-type carriage prevalence appears to be approaching equilibrium, yet residual carriage persists. Virtual elimination of PCV10-type carriage (≤1% in children <5 years; ≤3% in children 5-9 years) – a prerequisite for introduction of reduced dose schedules – is unlikely without implementation of additional strategies.